The present invention relates to an ultrasonic transducer, in particular, for distance warning/anti-collision devices in motor vehicles. These kinds of transducers have a piezoelectric disc that begins to oscillate when a voltage is applied. These oscillations are transmitted to an oscillating element, and it is known that at least one of the electrical connecting leads is taken to the piezoelectric disc via the oscillating element. This type of design, for example, is disclosed in the German patent application 196 01 656.8.
The transducers described above have the disadvantage that the electrical leads either have to be soldered directly to the piezoelectric element or are at least partially--run over the, preferably aluminum, oscillating element. This means that a permanent electrical connection has to be established between the supply lead and the oscillating element or the piezoelectric disc. In known solutions, the electrical lead is soldered directly to the piezoelectric disc or the lead is run into a groove on the aluminum oscillating element and caulked thereto. Both electrical connections can be critical and are not suitable for automated manufacturing. Another disadvantage is that the transducer normally is fitted with a damping element located above the disc in the oscillating element. Consequently, it also must be ensured that the electrical connecting leads are run through appropriate holes in the damping element, which further precludes a simple production process. In the known DE-OS 38 26 799, it already has been proposed to establish the connection by means of contact pins that can be joined with each other, in which case, however, the ends of the contact pins would also have to be permanently connected to the piezoelectrical crystal.
GB-OS 2 128 399 discloses an ultrasonic transducer, in which a printed circuit board is used as the electrical circuit. The printed circuit board itself has protruding resilient contact arms that come into biased contact with assigned contact points in the transducer. The contact arms are soldered to the printed circuit board and are led through the printed circuit board by way of assigned openings after the soldering process. In order to be able to align the printed circuit board within the pot-shaped transducer housing, it is held within a retaining bowl. As far as the contact making is concerned, this is a comparably complicated design.